diff --git a/doc/manual/src/SUMMARY.md.in b/doc/manual/src/SUMMARY.md.in
index 3de053a17..701a6ea69 100644
--- a/doc/manual/src/SUMMARY.md.in
+++ b/doc/manual/src/SUMMARY.md.in
@@ -100,7 +100,7 @@
   - [File System Object](architecture/file-system-object.md)
 - [Protocols](protocols/protocols.md)
   - [Serving Tarball Flakes](protocols/tarball-fetcher.md)
-  - [Derivation on-disk "ATerm" format](protocols/derivation-aterm.md)
+  - [Derivation "ATerm" file format](protocols/derivation-aterm.md)
 - [Glossary](glossary.md)
 - [Contributing](contributing/contributing.md)
   - [Hacking](contributing/hacking.md)
diff --git a/doc/manual/src/protocols/derivation-aterm.md b/doc/manual/src/protocols/derivation-aterm.md
index 2377e51ae..c9dc00ef7 100644
--- a/doc/manual/src/protocols/derivation-aterm.md
+++ b/doc/manual/src/protocols/derivation-aterm.md
@@ -1,4 +1,4 @@
-# Derivation on-disk "ATerm" format
+# Derivation "ATerm" file format
 
 For historical reasons, [derivations](@docroot@/glossary.md#gloss-store-derivation) are stored on-disk in [ATerm](https://homepages.cwi.nl/~daybuild/daily-books/technology/aterm-guide/aterm-guide.html) format.